subcritical
/ˌsʌbˈkrɪtɪkəl/adjective
1- Physics below a critical threshold, in particular【物理】临界值以下的, 尤指：
1.1
- (in nuclear physics) containing or involving less than the critical mass（核物理用语）次临界的。
1.2
- (of a flow of fluid) slower than the speed at which waves travel in the fluid（液流）次临界速度的。